Cooling Holes for Film Wrapped Articles

ABSTRACT

Holes in the film can be formed after film wrapping the bundle. Slits are formed in the heat shrink film prior to film wrapping the bundle. While the bundle moves through a heat shrink tunnel on a conveyor, the slits can be opened by increasing the shrinkage of the film surrounding the slit. This can be accomplished by directing high speed jets of hot air on the slits. Although slits are preferred the hot air can be used on any opening to increase the size of the opening.

FIELD OF INVENTION

This invention relates to cooling or freezing an article or a bundle ofarticles after the article has been filmed wrapped and heat shrunk. Theterm article refers to a bundle of articles such as bottles or a singlearticle. These articles are perishable and require a cooled environment.

BACKGROUND OF INVENTION

The prior art has placed articles in cartons, having holes in thecarton, to allow cold air to circulate in the carton during the freezingor cooling of the articles. This technique of cutting holes in the heatshrink film for air circulation of the article has been tried withoutsuccess. Cutting the holes mechanically with an heated die or heat whilethe heat shrink material is moving resulted in hole sizes of less thanabout ⅜ inch. The prior art was in need of a commercial viable way ofcreating openings large enough to allow sufficient air circulation tocool or freeze articles wrapped with a heat shrunk film.

The prior art, shown in U.S. patent application Ser. No. 13/972,078filed on Aug. 21, 2013 by Alain Cerf titled, Cooling film WrappedArticles, is incorporated by reference in the entirety. The applicationshows forming slits or slots in the longitudinal direction in a heatshrink film for allowing cooling air to circulate between the articleswhile maintaining the structural integrity of the heat shrunk film. Thisinvention was not always able to achieve openings of sufficient size forallowing cooling air to circulate between the articles

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a film 1 moving between a set of rollers 2 and 3.Adjustable blade 7 on pivot 6 is lowered to cut a slit in the film. Thelocation and the length of the slit is formed so that when a bundle ofarticles are film wrapped the slit 4 is located on the vertical sides ofthe bundle. FIG. 2 shows three vertical slits 4 and three vertical slits5 to be located on opposing vertical sides of the bundle. After filmwrapping the bundle moves through a heat shrink tunnel on a conveyorwhere the film is heat shrunk. Within in the tunnel, the slits areopened by increasing the shrinkage of the film surrounding the slit.This can be accomplished by directing high speed jets of hot air on theslits. Openings in excess of 20-25 mm can be achieved. FIG. 3 shows cupsof yogurt 7 having opened slits using jets of hot air.

After the film is heat shrunk, the wrapped article is transported to afreezer or cooler 7 to prevent spoilage of the contents within thebundle. The heat shrunk bundle can be bundled or palletized prior toentering the freezer or cooler.

1. A process for arranging an article or a bundle of articles wrappedwith heat shrink film so that cool air can circulate through the bundlecomprising, forming a slit in the film, locating the slit so the slit ispositioned on the vertical sides of the bundle during film wrapping,film wrapping the bundle, transporting the wrapped bundle to a heatshrink tunnel, heat shrinking the bundle, and increasing the opening ofthe slit during heat shrinking by increasing the heat shrinkage of thefilm surrounding the slit.
 2. A process according to claim 1 includingcooling the film wrapped article to prevent spoilage.
 3. A processaccording to claim 1 including multiple vertical slits located onopposing vertical sides of the bundle.
 4. A process according to claim 1wherein high speed jets of hot air are directed on the slit during heatshrinking of the film.
 5. An apparatus for arranging an article or abundle of articles wrapped with heat shrink film so that cool air cancirculate through the bundle comprising, means for forming a slit in thefilm, means for locating the slit so that the slit is positioned on thevertical sides of the bundle during film wrapping, means for filmwrapping the bundle, means for transporting the wrapped bundle to a heatshrink tunnel, means for heat shrinking the bundle, and means forincreasing the opening of the slit by increasing the heat shrinkage ofthe film surrounding the slit.
 6. An apparatus according to claim 5including means for cooling the film wrapped article to preventspoilage.
 7. An apparatus according to claim 5 including means forforming multiple vertical slits on opposing vertical sides of thebundle.
 8. An apparatus according to claim 5 wherein means for directinghigh speed jets of hot air on the slits during heat shrinking of thefilm.
 9. A process for arranging an article or a bundle of articleswrapped with heat shrink film so that cool air can circulate through thebundle comprising, forming an opening in the film, film wrapping thebundle, transporting the wrapped bundle to a heat shrink tunnel, heatshrinking the bundle, and increasing the size of the opening during heatshrinking by increasing the heat shrinkage of the film surrounding theopening.
 10. A process according to claim 9 wherein the opening is aslit.
 11. A process according to claim 9 wherein the heat shrinkage ofthe film is increased by directing high speed jets of hot air on thefilm surrounding the opening during heat shrinking of the film.